Escapement drive for counting mechanisms

ABSTRACT

An escapement drive for counting mechanisms, in which the pin pallet fork includes a pair of similar pivotally interconnected arms carrying, on the respective extremities thereof, facing the escape wheel, magnet members adapted to cooperate with the coils of an electromagnetic system. These arms are mounted for pivotal movement about respective axes equally spaced from the center of the escape wheel, so that the pallet pins of the arms are positioned to receive therebetween those of the teeth of the escape wheel, which lie on a diameter thereof, adjoining a line perpendicular to the arms.

United States Patent 151 3,685,277 [451 Aug. 22, 1972 Fedchenko [54] ESCAPEMENT DRIVE FOR COUNTING MECHANISMS [72] Inventor: Feodosy Mikhailovich Fedchenko, Solnechnogorsky raion, poselok Mendeleeveo, 20, kv. 8, Moskovaskaya Oblast, USSR. [22] Filed: Dec. 16, 1970 [21] Appl. No.: 98,545

[52] US. Cl ..58/23 D, 58/30, 58/116, 74/ l .5 [51] Int. Cl. ..G04c 3/02 [58] Field of Search ..58/23 D, 28, 29, 116, 123, 58/30; 74/l.5

[56] References Cited UNITED STATES PATENTS 3,201,932 8/1965 Sparing et al. ..58/23 V 3,020,425 2/1962 Steiner ..5 8/23 D Primary Examiner-Richard B. Wilkinson Assistant Examiner-Edith C. Simmons Jackmon Attorney-Holman & Stern ABSTRACT An escapement drive for counting mechanisms, in which the pin pallet fork includes a pair of similar pivotally interconnected arms carrying, on the respective extremities thereof, facing the escape wheel, magnet members adapted to cooperate with the coils of an electromagnetic system. These arms are mounted for pivotal movement about respective axes equally spaced from the center of the escape wheel, so that the pallet pins of the arms are positioned to receive therebetween those of the teeth of the escape wheel, which lie on a diameter thereof, adjoining a line perpendicular to the arms.

2 Claims, 2 Drawing Figures ESCAPEMENT DRIVE FOR COUNTING MECHANISMS BACKGROUND OF THE INVENTION The present invention relates to time counting mechanisms and instruments, and, more particularly to escapement drives for counting mechanisms, including escapement drives for high-precision secondary timepieces with second-wise operation.

PRIOR ART There is a known escapement drive for counting mechanisms, wherein electric current pulses coming from a primary pulse source are transformed into successive angular displacements of the associated count ing mechanism, with this transformation being performed with the help of an electromagnetic system operatively connected with a pallet pin fork, and the pallet pin fork is adapted to cooperate, by the pallet pins thereof, with the teeth of a toothed escape wheel.

In this known escapement drive, the pallet pin fork is an integral member, and the two pallet pins thereof operate under different physical conditions. One of the pins pushes the tooth of the escape wheel, which it engages, while the other pin pulls that one'of the teeth of the escape wheel, which it engages. One of the pins operates so that the convex portion of its arcuate path is the working one, while the other pin operates so that the shape of the working portion of its arcuate path is concave. The time of operation and the effort needed for the working stroke of one of the two pallet pins are different from those of the other pallet pin, and it is practically impossible to equalize them. This means that the operation of the entire escapement drive is inadvertently asymmetrical, whereby the operation of the associated counting mechanism is non-uniform.

The abovementioned disadvantages of the escapement drive have inhibited wide use of drives of this kind.

It is an object of the present invention to provide an escapement drive for counting mechanisms, which ensures uniform operation of the counting mechanisms.

It is another object of the present invention to provide an escapement drive for counting mechanisms, which positively prevents multifunctioning and lost steps in the operation of the counting mechanisms.

SUMMARY OF THE INVENTION With these and other objects in view, in an escape ment drive for counting mechanisms, in which successive electric current pulses, emanating from a primary pulse source are transformed into successive angular steps of the associated counting mechanism with the help of an electromagnetic system operatively connected with a pin pallet fork cooperating, by the pallet pins thereof, with the teeth of a toothed escape wheel, in accordance with the present invention, the pin pallet fork includes a pair of similar pivotally interconnected arms, with the arms carrying on the extremities thereof facing the escape wheel, a respective pair of arcuate magnet members adapted to cooperate with the coils of the electromagnetic system at moments, when electric current pulses are supplied thereto, with the radius of the curvature of the magnet members being equal to the length of the arms carrying the magnet members,

said two arms being mounted for pivotal movement about the respective pivot axes equally spaced from the center of the escape wheel, so that their respective pallet pins receive therebetween between a pair of the teeth of the escape wheel, which lie on a diameter of the wheel, with the diameter being near to a perpendicular between the two arms, and the two pallet pins being adapted to operate alternately, at moments when the coils of the magnetic system cooperate with the magnet members, whereby the associated counting mechanism is driven through successive unifomi angular steps in uniform time intervals.

It is advisable for the extremities of the arms, remote from the escape wheel, to carry counterweights adapted to balance the arms relative to the respective pivot axes thereof.

The structure of an escapement drive embodying the present invention makes it possible to provide an escapement drive for counting mechanisms, including secondary timepieces, which is characterized by simplicity, reliability of operation, compactness and versatility of applications. Due to the arms of the pallet pin fork being counterbalanced, counting mechanisms incorporating such escapement drives feature equally dependable operation in various special positions, as well as under considerable centrifugal and vibratory loads.

Other objects and advantages of the present invention will become apparent from the following detailed description of an embodiment thereof, with reference to the accompanying drawings, wherein:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows schematically an escapement drive mechanism embodying the invention; and

FIG. 2 shows the drive chain of a portion of the escapement drive mechanism, constructed in accordance with the invention, and of a high precision secondary timepiece with second-wise operation, associated with this escapement drive.

The escapement drive for counting devices, embodying the present invention, will be hereinafter disclosed in association with the counting mechanism of a highprecision secondary timepiece with second-wise operation.

DETAILED DESCRIPTION OF THE DRAWINGS Referring now in particular to the appended drawings, the present escapement drive comprises an electromagnetic system 1 (FIG. I) mounted on a support plate, with this electromagnetic system transforming electric current pulses coming from a primary pulse source into successive angular steps of the associated counting mechanism which, in the herein disclosed embodiment, is in the form of a high-precision secondary timepiece with second-wise operation, such transformation being preformed with the help of a pin pallet fork 2 cooperating, by means of cylindrical pins 3 and 4, with teeth 5 of an escape wheel 6 mounted for rotation on a central shaft 7 (the support plate, the primary pulse source. and the high-precision secondary timepiece not being shown in the drawing).

The pin pallet fork 2 includes a yoke 8 pivotally interconnecting a pair of identical substantially L-shaped arms 9 and 10 mounted for pivoting movement about a pair of pivot axes 11 and 12 respectively, and the two axes are equally spaced from the central shaft 7 of the toothed escape wheel 6.

The respective extremities of the arms 9 and 10, which are adjacent to the escape wheel 6 and electromagnet coils 13 and 14 of the electromagnetic system I, carry arcuate magnet members 15 and 16 adapted to cooperate with the coils l3 and 14 respectively when electric current pulses are supplied to the electromagnetic system 1, with the radius of curvature of the members 15 and 16 being equal to the length of their respective supporting arms, as measured from the pivot axes thereof. The extremities of the arms 9 and 10, opposite to the magnet members, carry counterweights l7 and 18 respectively adapted to balance their respective arms relative to the pivot axes thereof.

The arms 9 and 10 are supported on their respective pivot axes 1 1 and 12 in such a way that their pallet pins 3 and 4 which, in the herein disclosed embodiment, are mounted on the magnet members and 16, are positioned to cooperate withthose of the teeth 5 of the escape wheel 6, which lie on the diameter of the wheel 6, with the diameter being fairly adjacent to a line perpendicular to the arms 9 and 10, and the pallet pins 3 and 4 are adapted to engage alternately the teeth of the escape wheel, at moments when the electromagnet coils 13 and 14 actuate the respective arcuate magnet members 15 and 16, whereby the toothed wheel system of the associated high-precision secondary timepiece is driven through equal angular steps at equal time intervals.

In order to obtain a more complete and clear depiction of the escapement drive and of the association thereof with a counting mechanism, there is described a high-precision secondary timepiece with a secondwise operation incorporating the escapement drive embodying the invention, which is illustrated in FIG. 2.

Mounted on the rotation shaft 7 of the escape wheel 6 and which shaft 7 carries the seconds hand (not shown) of the timepiece, is a pinion 19 meshing with an intermediate toothed wheel 20 mounted for rotation on a central shaft 21. The central shaft 21 supports a pinion 22 frictionally engaging the toothed wheel 20, whereby a control head 23 can be selectively operated to set the minutes and the hours hands (not shown in the drawing) to a desired time indication. The seconds hand of the timepiece can be set by means of a pushbutton (not shown) adapted to energize a primary pulse source (not shown).

The pinion 22 sets into rotation a minutes toothed wheel 24 which rotates about an axis coinciding with that of the central shaft 7. A pinion 25 integral with the minutes wheel 24 transmits rotation to an intermediate toothed wheel 26 rotating on a central shaft 27. A pinion 28 integral with the wheel 26 transmits rotation to hours toothed wheel 29 which rotates about an axis coinciding with that of the shaft 7. In FIG. 2, numerals 30 and 31 indicate, respectively, the hollow central shafts of the minutes and hours hands.

The escapement drive operates, as follow:

The escapement drive is operated by electric current pulses of alternating polarity, supplied to the electromagnetic system 1 thereof from the primary pulse source.

The electromagnet coils l3 and 14 of the electromagnetic system 1 are electrically connected in series, so that their similar magnetic poles face in opposite directions, whereby, when the coils operate simultaneously, one of them attracts (i.e. retracting) and the other one repels (i.e. projecting) the respective ones of the arcuate magnet members 15 and 16. In the position illustrated in FIG. 1 the coil 13 is attracting the magnet member 15, whereas the coil 14 is repelling the magnet member 16. Consequently, the magnet member 15 and 16, together with their respective arms 9 and 10 swing from the right to the left, so that the pallet pin 3 disengages the corresponding tooth 5 of the escape wheel 6, while the pallet pin 4 engages the apex portion of the corresponding tooth 5 of the escape wheel 6, slides along the inclined surface of such tooth, whereby the escape wheel is rotated through a half of the pitch of its teeth, and at the end of its working stroke, the pin 4 arrests and retains the escape wheel 6. For the operation of the escape wheel to be maximally smooth and for the retaining thereof to be positive, the radial height of the teeth 5 is such that the angle between the adjacent teeth 5 approximates the jamming angle.

When the successive electric current pulse of the opposite polarity is supplied to the electromagnetic system 1, the above described operation is repeated in a similar manner, although in the opposite direction, i.e. the pallet pin 4 disengages the wheel 6, while the pallet pin 3 engages the corresponding tooth 5, slides along the inclined edge thereof, thus rotating the wheel 6 through another half of the pitch of the teeth 5 in the same direction of rotation, and at the end of its stroke, the pin 3 arrests and retains the wheel.

The escape wheel 6, as described above, is connected through the pinion 19 with the toothed wheel system of the associated high-precision secondary timepiece, whereby the successive angular steps of the escape wheel actuate the operation of the timepiece.

It can be seen that both of the two pallet pins 3 and 4 of the escapement drive mechanism, operate by push ing the corresponding teeth 5 of the escape wheel 6 under absolutely similar geometrical and physical conditions. If it is desirous to reverse the direction of the rotation of the escape wheel 6, it is sufficient to turnover the wheel 6 on its support shaft 7, i.e. mount the wheel on the shaft in the opposite plane thereof. In this case, the pallet pins 3 and 4 would operate not by pushing but by pulling the corresponding teeth 5 of the escape wheel 6, and their operation is absolutely symmetrical.

An escapement drive mechanism constructed in accordance with the present invention, due to its allpurpose character, makes it possible to manufacture, with the help thereof, a wide range of dependable and economical high-precision secondary timepieces with second-wise operation and with centrally located seconds hands of various sizes, as well as numerous other counting mechanisms.

There have been manufactured with the incorporation of the present escapement drives several highprecision secondary timepieces of various sizes, with dial diameters equalling mm, 300 mm and 1200 mm (all these timepieces being of second-wise opera tion and including a centrally located sweep seconds hands).

A test performed with one of the last-mentioned timepieces of a panel board-mounted type, having a 100 mm dial diameter, on a vibratory testing stand has shown that the timepiece would operate with the precision of its operation unaffected, even by vibratory overloads as high as g.

Moreover, secondary timepieces incorporating the present escapement drives have proved very economical. They can be operated with the supply voltage as low as 5 6 V, consuming an amount of electric energy which is but one fifth to one fourth of that consumed by mechanisms of similar sizes incorporating drive arrangements of different structures.

What we claim is:

1. An escapement drive mechanism for counting devices, in which electric current pulses emanating from a primary pulse source are converted into successive angular steps of a counting mechanism, comprising a support plate; an electromagnetic system including coils mounted on said support plate; the electromagnet coils of said electromagnetic system being connected to receive current pulses from said primary pulse source; an escape wheel mounted for rotation on said support plate; a plurality of teeth for said escape wheel; a second hand mounted on the rotational axis of the escape wheel; a first pivot axis supported by said sup port plate; a second pivot axis supported by said support plate, said first and said second pivot axes being equally spaced from the center of said escape wheel; a first arm pivotally mounted on said first pivot axis; a second arm pivotally mounted on said second pivot axes, said second arm being similar to said first arm and being pivotally connected with the first arm; a first arcuate magnet member supported on an extremity of said first arm, said first magnet member facing said escape wheel, and adapted to cooperate with said coils of said electromagnetic system, when said current pulses are supplied thereto; a second arcuate magnet member supported on an extremity of said second arm, said second magnet member facing said escape wheel, and adapted to cooperate with said coils of said electromagnetic system, when said current pulses are supplied thereto; the radius of curvature of said first and second arcuate magnet members being equal to the length of their respective arms from said respective pivot axes thereof; pallet pin means carried by each of said first and second arms; the pivot axis of one of said arms being disposed to one side of a straight line passing through the center of said escape wheel by an angle equal to half the pitch of the teeth of the escape wheel so that each of the pallet pin means moves the escape wheel precisely through half the pitch of the teeth thus ensuring a symmetric operation; said pallet pin means being arranged on said arms at a distance less than the diameter of the escape wheel; said respective ones of said pallet pin means being adapted to operate alternately at moments, when said coils of said electromagnetic system cooperate with said arcuate magnet members, whereby said current pulses are transformed into successive equal angular steps of said counting mechanism in equal time intervals.

2. The escapement drive mechanism, as claimed in claim 1, wherein the respective extremities of said first and said second arms, remote from said escape wheel,

have mounted thereon respective counterweight means adapted to balance said respective arms relative to said respective pivot axes thereof. 

1. An escapement drive mechanism for counting devices, in which electric current pulses emanating from a primary pulse source are converted into successive angular steps of a counting mechanism, comprising a support plate; an electromagnetic system including coils mounted on said support plate; the electromagnet coils of said electromagnetic system being connected to receive current pulses from said primary pulse source; an escape wheel mounted for rotation on said support plate; a plurality of teeth for said escape wheel; a second hand mounted on the rotational axis of the escape wheel; a first pivot axis supported by said support plate; a second pivot axis supported by said support plate, said first and said second pivot axes being equally spaced from the center of said escape wheel; a first arm pivotally mounted on said first pivot axis; a second arm pivotally mounted on said second pivot axes, said second arm being similar to said first arm and being pivotally connected with the first arm; a first arcuate magnet member supported on an extremity of said first arm, said first magnet member facing said escape wheel, and adapted to cooperate with said coils of said electromagnetic system, when said current pulses are supplied thereto; a second arcuate magnet member supported on an extremity of said second arm, said second magnet member facing said escape wheel, and adapted to cooperate with said coils Of said electromagnetic system, when said current pulses are supplied thereto; the radius of curvature of said first and second arcuate magnet members being equal to the length of their respective arms from said respective pivot axes thereof; pallet pin means carried by each of said first and second arms; the pivot axis of one of said arms being disposed to one side of a straight line passing through the center of said escape wheel by an angle equal to half the pitch of the teeth of the escape wheel so that each of the pallet pin means moves the escape wheel precisely through half the pitch of the teeth thus ensuring a symmetric operation; said pallet pin means being arranged on said arms at a distance less than the diameter of the escape wheel; said respective ones of said pallet pin means being adapted to operate alternately at moments, when said coils of said electromagnetic system cooperate with said arcuate magnet members, whereby said current pulses are transformed into successive equal angular steps of said counting mechanism in equal time intervals.
 2. The escapement drive mechanism, as claimed in claim 1, wherein the respective extremities of said first and said second arms, remote from said escape wheel, have mounted thereon respective counterweight means adapted to balance said respective arms relative to said respective pivot axes thereof. 